GF07.61-P-4027MAR Overheating/Pinging Protection, Function

GF07.61-P-4027MAR Overheating/Pinging Protection, Function
- refinement package
- as of model year 09


Function requirements for overheating/knock protection, general points
^ Circuit 87M ON (engine control ON)
^ Engine running

Overheating/knock protection, general points
In the event of thermal overload, the overheating/knock protection protects against engine damage and prevents overheating damage to the firewall catalytic converters.
The ME-SFI control unit (N3/10) controls the overheating/knock protection according to information from the following sensors:
- LH and RH hot film MAF sensor (B2/6, B2/7), engine load
- Coolant temperature sensor (B11/4)
- Intake air temperature sensor (B17)
- Crankshaft Hall sensor (B70), motor speed

Overheating/knock protection function sequence
If coolant or intake air temperature is too high, the ME-SFI control unit no longer fully opens the front and rear throttle valve actuators (M16/3, M16/4), depending on engine speed and load. The ME-SFI control unit shortens the injection time of the fuel injection valves (Y62) according to the lower air mass.

The ME-SFI control unit also actuates the two-disk thermostat heating element (R48), so that the two-disk thermostat is fully opened and all the coolant is cooled by the engine radiator.